Room: Exhibit Hall | Forum 3
Purpose: This work studies a novel treatment technique that uses high-energy radiation in combination with photosensitizers and oxidizing agents to treat deep seated tumors. The purpose of this study is to investigate treatment efficacy by characterizing the effect on tumor growth of initial trials using radiotherapy (RT) combined with both 5-aminolevulinic acid (5-ALA) and carbamide peroxide, using a mouse model.
Methods: Male nude mice were injected with human prostate cancer (PC-3) cells subcutaneously bilaterally into their flanks. The tumors (n=223) were randomized into 7 groups, including an untreated group and various combinations of RT, 5-ALA, and peroxide in order to determine the individual and synergistic effects of the treatment components. 5-ALA was administered ~4 hours prior to RT by tail-vein injection at a concentration of 100 mg/kg, while 60 mg/kg of carbamide peroxide was administered directly into tumors immediately before RT. Efficacy was monitored with weekly MR scans using a GE Signa 1.5T MR scanner, followed by measurement of tumor volume growth. To verify that blood perfusion in the tumors was adequate to deliver the 5-ALA, Â¹â?¸F-FDG PET/CT studies as well as measurements of 5-ALA fluorescence in the tumors were performed.
Results: Tumors treated with RT and 5-ALA/carbamide peroxide increased by a factor of 1.65Â±0.11 and 2.61Â±0.23 one and two weeks post-treatment, compared with an increase of 2.08Â±0.16 and 4.25Â±0.49 for RT alone and of 2.63Â±0.24 and 7.27Â±0.77 for the control group, respectively. Peroxide and 5-ALA were shown to contribute negligibly to tumor growth delay when administered alone or separately with RT. Blood perfusion was shown to be able to deliver agents to the tumors investigated in this work.
Conclusion: RT combined with 5-ALA and carbamide peroxide resulted in a more significant tumor growth delay at one and two weeks compared to its constituents individually in this initial study.
Not Applicable / None Entered.